A two-dimensional semiconductor (also known as a 2D semiconductor) is a type of natural semiconductor with thicknesses on the atomic scale. A 2D monolayer semiconductor is significant because it exhibits stronger piezoelectric coupling than traditionally employed bulk forms, which enables 2D materials applications in new electronic components used for sensing and actuating. Transition metal dichalcogenides have been used in 2D devices. Performance of single 2D transition metal dichalcogenide materials for device applications is reaching an upper limit. Because 2D materials are very thin, as thin as a single monolayer, etching 2D materials is difficult to do without damaging the remaining unetched portions of the 2D materials.